Sequence for Brake Testing

Hi There,

I am working with a Dewe 43A to conduct some basic brake tests on our transit trains. Using train speed, brake signal and accelerometer signal inputs to the unit I record a accelerate/decelerate speed curve to calculate the stopping distance and brake rates.

Since we are testing different brake modes on different trains, I was wondering if I can use the Sequencer to generate a startup interface where it will require you to enter the date and train number and choose a brake mode before starting the recording and when the recording is stopped it will save the file with the entered info. I am new to the software, so if you can show a sample file if this is possible, it would be great.

Thank you,

Sam

Hi,

I've created an example setup and sequence that uses a form block, which asks the user to input the date and select a train from a drop-down menu. It stores those two values as text in the sequencer variables, and then uses them to create a custom file name.

I'd like some more information about choosing between different brake modes. Could you maybe upload your setup file or a picture that shows which options you'd like to switch between? You could create a different display for each brake test tab, and then use the sequencer to only show the display that is linked with the selected test. I've added this option in the example. Depending on which test you choose, different visual controls will be displayed on your screen.

I think I am almost there in getting the sequence to work as required. I can't seem to get the variable values to appear as the file name in the data files, automatically. See attached zipped folder for the files. Also is there a way to get the date to appear in the file name automatically instead of typing it ? I know you can set this up under 'storage' options, but I do that then the sequence store file name option does not work.

Thanks again for the help

Hi,

you need to use single quotation marks around the variable's name. In your case, you should use 'car'.dxd, 'date'.dxd or a combination like 'car'.'date'.dxd. Another problem with your sequence was that the form wasn't linked with the correct variable, because you used both single and double quotation marks on one side of the variable, which I've marked in the attached picture.

You can read the date automatically by using the calculation block with the SysDateTime("<format>") function. You can use standard Delphi date formats, which can be found on this webpage.

I've fixed the automatic file naming and have added a date reader example to your sequence.

Great ! after a few more tweaks the sequencer file works now, thanks.

Also, I was wondering is it possible to use a variable that is taken from a user form during the sequence and use it in the setup file in a math formula ? I like to incorporate a form for the user to enter the wheel diameter of the train before the brake test, which will be used in the distance calculation of the setup.

Hi,

glad to hear it's working. You can use the values that a user inputs in the sequencer with a math formula, but you need to assign it to a user input channel. I've added another line to your form which asks the user to input a number. This number is assigned to the sequencer variable called "Math variable". When you start the measurement, a calculation block is used to take the value from this variable and assign it to the user input channel named "Input variable". On the measurement screen you can see two digital meters, one displays the original value that the user had entered, while the other multiples it by 25 to prove that the math channel is working.

I want to compare my acquired brake rate to a set rate, and show a "PASS" OR "FAIL" message in when the measurement is stopped, (in the measure screen). I can make the formula to compare the rates and generate a 1 or 0, but is there a way to display this number in terms of a string ?

Thanks.

Hi There,

Also, I added an IF block to my sequence for some value comparision, but I keep getting a "Warning (If): No Samples acquired" Error. I can see the channel that I am using to compare in the If block incrementing, so I know it is aquireing data, but the error keeps popping up. Can you please explain why this error is generated ? Also is there a document that explains all the errors generated in the Sequencer ?

Thank you,